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41.
Journal of Soils and Sediments - The aims of the study were to investigate the interaction between fractions of organic matter and polycyclic aromatic hydrocarbons (PAHs) in bottom sediments and to...  相似文献   
42.
To assess strategies for mitigating Pb and As transfer into leafy vegetables from contaminated garden soils, we conducted greenhouse experiments using two field-contaminated soils amended with materials expected to reduce metal phytoavailability. Lettuce and mustard greens grown on these soils were analyzed by ICP-MS, showing that some Pb and As transfer into the vegetables occurred from both soils tested, but plant Pb concentrations were highly variable among treatment replicates. Soil-to-plant transfer was more efficient for As than for Pb. Contamination of the leaves by soil particles probably accounted for most of the vegetable Pb, since plant Pb concentrations were correlated to plant tissue concentrations of the immobile soil elements Al and Fe. This correlation was not observed for vegetable As concentrations, evidence that most of the soil-to-plant transfer for this toxic metal occurred by root uptake and translocation into the above-ground tissues. A follow-up greenhouse experiment with lettuce on one of the two contaminated soils revealed a lower and less variable foliar Pb concentration than observed in the first experiment, with evidence of less soil particle contamination of the crop. This reduced transfer of Pb to the crop appeared to be a physical effect attributable to the greater biomass causing reduced overall exposure of the above-ground tissues to the soil surface. Attempts to reduce soil Pb and As solubility and plant uptake by amendment at practical rates with stabilizing materials, including composts, peat, Ca phosphate, gypsum, and Fe oxide, were generally unsuccessful. Only Fe oxide reduced soluble As in the soil, but this effect did not persist. Phosphate amendment rapidly increased soil As solubility but had no measurable effect on either soil Pb solubility or concentrations of Pb or As in the leafy vegetables. The ineffectiveness of these amendments in reducing Pb transfer into leafy vegetables is attributed in this study to the low initial Pb solubility of the studied soils and the fact that the primary mechanism of Pb transfer is physical contamination.  相似文献   
43.
This paper presents the effects of particle size and mixing ratio on the properties including physical, mechanical, and decay resistance of wood plastic composites (WPCs). In addition, it also presents the effects of immersion temperatures on water absorption (WA) and thickness swelling (TS) of the WPCs. WPCs with a thickness of 6 mm were fabricated from Albizia richardiana King & Prain wood particles and recycled polyethylene terephthalate (PET) by the flat-press method. To prepare the WPCs, two different wood particle sizes (0.5–1.0 and 1.01–2.0 mm) were used along with four different mixing ratios (w/w). Subsequently, the physical properties include density, moisture content, WA, and TS, and mechanical properties include modulus of elasticity (MOE) and modulus of rupture (MOR) of the produced WPCs was evaluated. Furthermore, decay resistance was evaluated by the weight loss percentage method. Moreover, the effects of immersion temperatures on WA and TS of WPCs after 24 h of immersion in water at three different temperatures, i.e., 25, 50, and 75 °C were investigated. Results showed that the wood particle size had impact on WPC’s density (only 6% decreased with the increase of particle size); however, the density decreased by 29% when the wood particle content increased from 40 to 70%. The WA and TS gradually increased with the increase of particle content and decrease of particle size. In addition, WA and TS increased proportionately with increasing immersion temperature from 25 to 75 °C. Furthermore, the highest MOE (2570 N/mm2) was found for the WPCs fabricated from large wood particles having the ration of 50:50 (wood particle:PET). For decay resistance, WPCs consisted of larger particles and higher PET content showed greater resistance against decay. Therefore, it is comprehensible that fabrication of the WPCs from 50% large particles and 50% PET is technically feasible and further improvement of WPC performance like enhancement of MOE and reduction of density using coupling agent and agricultural waste fibers, respectively, in the WPC formulation is recommended.  相似文献   
44.
Coenzyme Q10 (CoQ10) has been extensively studied as adjunctive therapy for ischemic heart disease, and its cardioprotective ability is well-established. The mitochondrial respiratory chain contains several coenzymes, including CoQ1, CoQ2, CoQ4, CoQ6, CoQ7, CoQ8, CoQ9, and CoQ10. It is not known whether other CoQs, especially CoQ9, is equally cardioprotective as CoQ10. The present study was designed to determine if CoQ 9 could protect guinea pig hearts from ischemia reperfusion injury. Guinea pigs were randomly divided into three groups: groups I and II were fed CoQ 9 and CoQ10, respectively, for 30 days while group III served as control. After 30 days, the guinea pigs were sacrificed and isolated hearts were perfused via working mode were subjected to 30 min ischemia followed by 2 h of reperfusion. Cardioprotection was assessed by evaluating left ventricular function, ventricular arrhythmias, myocardial infarct size, and cardiomyocyte apoptosis. Samples of hearts were examined for the presence of CoQ9 and CoQ10. The results demonstrated that both CoQ9 and CoQ10 were equally cardioprotective, as evidenced by their abilities to improve left ventricular performance and to reduce myocardial infarct size and cardiomyocyte apoptosis. High performance liquid chromatographic (HPLC) analysis revealed that a substantial portion of CoQ9 had been converted into CoQ10. The results indicate that CoQ9 by itself, or after being converted into CoQ10, reduced myocardial ischemia/reperfusion-induced injury.  相似文献   
45.
Some minerals can influence some biochemical parameters of rumen fermentation. The objective of this experiment was to determine the effect of different amounts (0.1, 0.25 and 0.5 g) of dolomite and to compare the effect of dolomite, magnesium oxide (MgO) and chalk (CaCO3) upon the end products of rumen fermentation in vitro. Amorphous and crystalline cellulose as well as meadow hay were used as substrates and incubated with buffered rumen fluid in sealed fermentation bottles. In dependence on the amount of dolomite and the kind of substrate an inhibitory effect of dolomite on methane production was evident. Significant differences of methane production were found between the controls, crystalline cellulose and meadow hay with 0.5 g of dolomite. An increase of total gas production was observed for cellulose with both 0.25 and 0.5 g of dolomite and also for meadow hay with 0.5 g of dolomite. It can be concluded that there was a remarkable effect of dolomite on methane production and also a slight effect of magnesium oxide and chalk as compared to the effect of dolomite on the fermentation parameters of incubated substrates.  相似文献   
46.
The effect of application of omega-3 polyunsaturated fatty acids (omega-3 PUFA) on intestinal colonization by Lactobacillus paracasei and on cellular immunity has been investigated in gnotobiotic pigs. The administration of polyunsaturated fatty acids positively affected the adhesion of Lactobacillus paracasei to the jejunal mucosa of gnotobiotic piglets. When compared to the control group, the number of Lactobacillus paracasei adhering to the jejunal mucosa was by 12% higher in piglets of the experimental group (5.10 log 10/cm2 vs. 4.55 log 10/cm2). The respective counts of Lactobacillus paracasei adhering to the ileal and colonic mucosa of 28 day old gnotobiotic piglets reached 4.45 and 5.05 log 10/cm2 in group C and 4.44 and 4.95 log 10/cm2 in group E. Omega-3 PUFA supplementation increased the phagocytic activity of neutrophils by almost 100% on day 28 of life as well as the subpopulations of lymphocytes (CD8) in the peripheral blood of germ-free piglets on day 21 of life. Our results indicate that the action of probiotics in the gut may be modulated by dietary PUFA. The stimulatory effect of PUFA upon adhesion of lactobacilli could be used for enhancing the effectiveness of probiotics in inhibiting digestive tract pathogens.  相似文献   
47.
Effect of pectinase on rumen fermentation in sheep and lambs   总被引:1,自引:0,他引:1  
In trial with adult wethers and weaned lambs the effect of enzymatic preparation Pektofoetidin G3x (mostly pectinase and cellulase) on rumen fermentation was studied. After 4 weeks of Pektofoetidin G3x application (0.54 g per day and animal) to adult wethers no statistically significant differences in total volatile fatty acids (VFA), acetic acid, propionic acid, butyric acid, ammonia in the rumen contents and urea in blood were determined between control and enzyme treated group. In comparison of fermentation parameters in wethers (mean of 1-3 hours after feeding) and lambs (2-3 hours after feeding) the significant differences in mol % of acetic acid (63.3 in control, 54.6 in experimental group, P less than 0.01), propionic acid (24.6, vs. 31.3, P less than 0.001), acetate: proprionate ratio (2.54, vs. 1.77, P less than 0.01) and in energy efficiency of VFA production (76.0%, vs. 79.1%, P less than 0.001) were determined. These differences between wethers and lambs suggest more intensive fermentation in lambs than in adult sheep. On the basis of these results it is possible to suggest, that in adult animals the efficiency of application of enzymatic preparations is low. In utilization of enzymatic preparations more important role, probably, is that of ruminal ecosystem itself, that, if once fully developed, is perfectly resistant to biotechnological interferences.  相似文献   
48.
Wethers were studied for the effect of the complete pelleted feed ration on the intake of water and concentration of pH and ammonia in the rumen. The animals consumed daily 1300 g of dry matter of the diet containing 41.81% of meadow hay, 25.8% of barley, 15.37% of sawdust, 14.98% of molasses, 1.32% of urea and 1.24% of vitamin mineral supplement. This feed was given to them for six months. The pelleted diet increased the intake of water (the dry matter consumption remaining the same in the control and experimental group), reduced pH concentration (6.0--6.2) and slightly increased the level of ammonia in the first hour after feeding; this was probably due to a rapid release of nitrogen compounds from the feed and to intensive rumen fermentation.  相似文献   
49.
The determination of the nutritive value of various secondary wood products was conducted by the method of the in-vitro digestibility of dry matter (Mellenberger et al., 1970) and by detergent analyses of fibre (Goering and Van Soest, 1970). Rumen contents for trials in vitro were obtained from adult wethers having a permanent rumen fistula and fed good meadow hay ad lib. The animals also had free access to water and mineral lick for sheep. Out of the 11 lignocellulose materials tested, digestibility in vitro higher than 60% (equivalent to the digestibility of high-quality meadow hay) was only found in three samples. These are: a) beech sawdust II treated with 0.1M sulphuric acid at the hydromodulus of 1:8, temperature 100 to 130 degrees C for two hours, and pressure of 0.25 MPa and then with 0.47M nitric acid at the hydromodulus of 1:13, temperature 100 degrees C for two hours and pressure of 0.25 MPa; b) beech sawdust III treated as beech sawdust II and then neutralized with ammonia to pH 8; c) aspen sawdust treated hydrobarothermically at a temperature of 280 degrees C and pressure of 7 MPa in saturated vapour medium (Canon system). The high digestibility of these samples was due to a low lignin content so that the polysaccharides (cellulose and hemicelluloses) of these secondary wood sources could be sufficiently utilized by rumen microflora.  相似文献   
50.
Growing interest in sustainable agriculture has prompted this study aiming to evaluate nutritional content of rice grain produced from an organic production system. Here, we grew nine quality rice cultivars under organic methods in the wet and dry seasons, and the nutritional values, grain quality, and physiological parameters were compared with respective cultivars grown under the standard cultivation method (SCM). Obtained results revealed that the yield and plant height were lower, but tillering capacity was higher, in the organic field compared with the standard one. The organic crop showed significantly lower contents of protein and phytate compared with reference values under the SCM. Antioxidative capacity and its responsible phytochemicals such as phenolics, flavonoids, and γ‐oryzanol were also significantly higher under organic cultivation than under the SCM. Among physicochemical characteristics, apparent amylose content, gel consistency, and area and perimeter of grain were also higher in the organic crops, but hulling quality, milling quality, head rice recovery, and all other cooking qualities were at par. Higher crude oil and lower total protein content of rice bran were observed in the organic crop, but ash, fiber, and moisture contents did not vary significantly in these two cultivation systems.  相似文献   
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